The study proposes an application of Talens (2003) methodological framework for assessing neighbourhood-level (i.e., non-motorised mode) accessibility, and offers recommendations for improving non-motorized transportation (NMT) accessibility to enhance multimodal integration between bicycles and buses in contemporary North American suburban neighbourhoods. Accessibility (or access) is defined as the average travel time or distance between a given origin and destination along the shortest available street network route. The study considers characteristics of the transportation network such as available route directness, facilities, and transit service provision to determine their impacts on bicycle access. A further methodology for comparing bicycle versus bus modal efficiencies within suburban contexts is developed and applied to the case study. A review of approaches designed to promote bicycling while discouraging personal automobile use provides a toolbox of proven treatments that are applied to a case study of Saskatoon, Saskatchewan a city of approximately 200,000 people. The approach provides a process that can be used by city or transit planners to identify neighbourhoods that lack sufficient access and apply treatments that improve bicycle accessibility and bicycle-transit integration. Results suggest existing potential for the bicycle as an access mode within contemporary suburban neighbourhood transportation networks. The case study supports the notion that suburban bicycle-bus integration could be used as a viable alternative to automobiles for daily home-to-node activity trips, and raises questions about the current allocation of public transit service to suburban routes within the context of the case study. Discussion and conclusions suggest directions for future research in this field of sustainable urban transportation planning.

Recent developments in data packets based high speed digital communications have opened the door for new types of applications in power system protection and control. Intelligent Electronic Devices (IEDs) are equipped with various communication capabilities that make their functional integration a natural next step. Existing integration of substation equipment is not capable of clustering with the purpose of pooling hardware resources. <p> Presently, every electric device requiring protection has its dedicated hardware performing the predetermined set of protective functions. A new function-based protection and control philosophy is proposed, based on an open-system solution. In the proposed system, the resources of the protective and control hardware are pooled, and as a clustered system provide each protected unit (line, transformer, breaker, etc) with functions required for complete direct and backup protection. <p> The work presented in this thesis identifies the performance requirements of a digital relaying algorithm for processing samples that are sent across Ethernet-based communication channels. The work shows the shortcomings and unstable performance of widely used protective algorithms in accommodating data samples that are out of step from their proper position due to variable time delays of the communications media. A new digital relaying algorithm was developed that is able to extract the amplitude and phase angle of signals from data samples received across Ethernet networks with variable jitter. <p> The performance of the algorithm was tested by using the recovered phasor amplitude and phase angle information in protective solutions. The results show that there is significant flexibility in the algorithm that can be used to facilitate less performant communication channels, or, to take advantage of faster communications channels by reducing the response time of the protective function. <p> The results show that the algorithm works well with variable length data windows, and variable sampling frequencies. Higher sampling rates make communications problems more visible, but the presented algorithm is able to compensate for wide variations in network performance, effectively maintaining sampled signal phase and amplitude information during network performance fluctuations.

The bus industry is plagued by high accident costs and risks of passenger injuries. A bus simulator may offer a method of reducing accident rates by delivering targeted training to bus drivers who are most at risk. The first part of this thesis describes the design of the UK's first bus simulator, the fidelity of which was based on a thorough analysis of bus crashes. The second part describes the first studies in a multi-staged method to evaluate the training effectiveness of the simulator: face validity, effects of bus driver experience and stress on simulated performance and simulator sickness. This approach ensured that the ABS has a reasonable level of fidelity, is capable of eliciting behaviourally valid responses from bus drivers and is the first step is achieving training transfer effectiveness. The final study investigated the occurrence of self-bias in bus drivers. The conclusions drove the design of simulated scenarios to be used for bus driver training. Keywords: Bus, Simulator, Fidelity, Validity, Accidents, Driving, Stress, Training

Fuel cells (FC) are electrochemical devices that directly convert the chemical energy of a fuel into electricity. Power systems based on proton exchange membrane fuel cell (PEMFC) technology have been the object of increasing attention in recent years as they appear very promising in both stationary and mobile applications due to their high efficiency, low operating temperature allowing fast startup, high power density, solid electrolyte, long cell and stack life, low corrosion, excellent dynamic response with respect to the other FCs, and nonpolluting emissions to the environment if the hydrogen is obtained from renewable sources. The output-voltage characteristic in a PEMFC is limited by the mechanical devices which are used for regulating the air flow in its cathode, the hydrogen flow in its anode, its inner temperature, and the humidity of the air supplied to it. Usually, the FC time constants are dominated by the fuel delivery system, in particular by the slow dynamics of the compressor responsible for supplying the oxygen. As a consequence, a fast load transient demand could cause a high voltage drop in a short time known as oxygen starvation phenomenon that is harmful for the FC. Thus, FCs are considered as a slow dynamic response equipment with respect to the load transient requirements. Therefore, batteries, ultracapacitors or other auxiliary power sources are needed to support the operation of the FC in order to ensure a fast response to any load power transient. The resulting systems, known as FC hybrid systems, can limit the slope of the current or the power generated by the FC with the use of current-controlled dc-dc converters. In this way, the reactant gas starvation phenomena can be avoided and the system can operate with higher efficiency. The purpose of this thesis is the design of a DC-DC converter suitable to interconnect all the different elements in a PEMFC-hybrid 48-V DC bus. Since the converter could be placed between elements with very different voltage levels, a buck-boost structure has been selected. Especially to fulfill the low ripple requirements of the PEMFCs, but also those of the auxiliary storage elements and loads, our structure has inductors in series at both its input and its output. Magnetically coupling these inductors and adding a damping network to its intermediate capacitor we have designed an easily controllable converter with second-order-buck-like dominant dynamics. This new proposed topology has high efficiency and wide bandwidth acting either as a voltage or as a current regulator. The magnetic coupling allows to control with similar performances the input or the output inductor currents. This characteristic is very useful because the designed current-controlled converter is able to withstand shortcircuits at its output and, when connected to the FC, it facilitates to regulate the current extracted from the FC to avoid the oxygen starvation phenomenon. Testing in a safe way the converter connected to the FC required to build an FC simulator that was subsequently improved by developing an emulator that offered real-time processing and oxygen-starvation indication. To study the developed converters and emulators with different brands of PEMFCs it was necessary to reactivate long-time inactive Palcan FCs. Since the results provided by the manual reactivation procedure were unsatisfactory, an automatic reactivation system has been developed as a complementary study of the thesis. / En esta tesis se avanzo en el diseño de un bus DC de 48 V que utiliza como elemento principal de generación de energía eléctrica una pila de combustible. Debido a que la dinámica de las pilas de combustible están limitadas por sus elementos mecánicos auxiliares de control una variación rápida de una carga conectada a ella puede ocasionar daños. Es por esto que es necesario utilizar elementos almacenadores de energía que puedan suministrar estas rápidas variaciones de carga y convertidores para que gestionen de una forma controlada la potencia del bus DC. Durante la realización de pruebas de los convertidores es de gran importancia utilizar emuladores o simuladores de pilas de combustibles, esto nos permite de una forma económica y segura realizar pruebas criticas antes de conectar los convertidores a la pila. Adicionalmente una nueva topologia de convertidor fue presentada y ésta gestionará la potencia en el bus

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This thesis will investigate the possibilities to wireless communicate within time critical applications with the radio protocol IEEE 802.15.4. IEEE 802.15.4 is a very quick protocol so the delays and jitter can be ignored in a small network. The thesis handles the question: Is it possible to split a CAN-bus and send the data via radio to the other side of the CAN-bus? The big problems with this are: • Will it be treated like a transparent link and not disturb the original functionality? • How does a system which is split up by radio treat new nodes on the bus? • What will be the maximum speed and the maximum utilization factor for the split up bus? • What new suitable protocols can be implemented on a higher level to get the split bus to work? This is modeled and discussed, real measurement from a radio link is used in the model to see if it’s possible. The radio communication will satisfy the demands from the company regarding their application. With an efficient error handling and a smart transmission protocol the application can be a very smart way of sending CAN-data via radio. / Denna rapport undersöker möjligheterna med att kommunicera trådlöst i tidskritiska applikationer med hjälp av radioprotokollet IEEE 802.15.4. IEEE 802.15.4 är ett väldigt snabbt protokoll så jitter och fördröjningen i sändningarna kan försummas för så små nätverk som tas upp i denna uppsats. Går det att bryta en CAN-buss och koppla in denna radiolänk så att den uppfattas som transparent? Många problem kommer att dyka upp om detta görs, några av dem är dessa: • Hur behandlar ett system nya noder som kopplas in om CAN-bussen är uppdelad? • Vilken är den maximala hastigheten och utnyttjandefaktor som kan uppnås av den delade CAN-bussen? • Måste ett överliggande protokoll användas för att sköta om datatrafiken mellan bussarna? Detta modelleras och diskuteras efter det att de uppmätta mätvärdena har samlats in och analyserats. Det som framkom var att det fungerar väldigt bra, data kommer fram i tid och felen i radiosändningarna är väldigt små. Med en väl genomtänkt felhantering och ett likaså genomtänkt omsändningsprotokoll kommer detta att fungera väldigt bra beroende på avstånd och antennval.

Recent developments in data packets based high speed digital communications have opened the door for new types of applications in power system protection and control. Intelligent Electronic Devices (IEDs) are equipped with various communication capabilities that make their functional integration a natural next step. Existing integration of substation equipment is not capable of clustering with the purpose of pooling hardware resources. <p> Presently, every electric device requiring protection has its dedicated hardware performing the predetermined set of protective functions. A new function-based protection and control philosophy is proposed, based on an open-system solution. In the proposed system, the resources of the protective and control hardware are pooled, and as a clustered system provide each protected unit (line, transformer, breaker, etc) with functions required for complete direct and backup protection. <p> The work presented in this thesis identifies the performance requirements of a digital relaying algorithm for processing samples that are sent across Ethernet-based communication channels. The work shows the shortcomings and unstable performance of widely used protective algorithms in accommodating data samples that are out of step from their proper position due to variable time delays of the communications media. A new digital relaying algorithm was developed that is able to extract the amplitude and phase angle of signals from data samples received across Ethernet networks with variable jitter. <p> The performance of the algorithm was tested by using the recovered phasor amplitude and phase angle information in protective solutions. The results show that there is significant flexibility in the algorithm that can be used to facilitate less performant communication channels, or, to take advantage of faster communications channels by reducing the response time of the protective function. <p> The results show that the algorithm works well with variable length data windows, and variable sampling frequencies. Higher sampling rates make communications problems more visible, but the presented algorithm is able to compensate for wide variations in network performance, effectively maintaining sampled signal phase and amplitude information during network performance fluctuations.

The study proposes an application of Talens (2003) methodological framework for assessing neighbourhood-level (i.e., non-motorised mode) accessibility, and offers recommendations for improving non-motorized transportation (NMT) accessibility to enhance multimodal integration between bicycles and buses in contemporary North American suburban neighbourhoods. Accessibility (or access) is defined as the average travel time or distance between a given origin and destination along the shortest available street network route. The study considers characteristics of the transportation network such as available route directness, facilities, and transit service provision to determine their impacts on bicycle access. A further methodology for comparing bicycle versus bus modal efficiencies within suburban contexts is developed and applied to the case study. A review of approaches designed to promote bicycling while discouraging personal automobile use provides a toolbox of proven treatments that are applied to a case study of Saskatoon, Saskatchewan a city of approximately 200,000 people. The approach provides a process that can be used by city or transit planners to identify neighbourhoods that lack sufficient access and apply treatments that improve bicycle accessibility and bicycle-transit integration. Results suggest existing potential for the bicycle as an access mode within contemporary suburban neighbourhood transportation networks. The case study supports the notion that suburban bicycle-bus integration could be used as a viable alternative to automobiles for daily home-to-node activity trips, and raises questions about the current allocation of public transit service to suburban routes within the context of the case study. Discussion and conclusions suggest directions for future research in this field of sustainable urban transportation planning.

Heavy-duty diesel vehicle (HDDV) operations are a major source of pollutant emissions in major metropolitan areas. Accurate estimation of heavy-duty diesel vehicle emissions is essential in air quality planning efforts because highway and non-road heavy-duty diesel emissions account for a significant fraction of the oxides of nitrogen (NOx) and particulate matter (PM) emissions inventories. Yet, major modeling deficiencies in the current MOBILE6 modeling approach for heavy-duty diesel vehicles have been widely recognized for more than ten years. While the most recent MOBILE6.2 model integrates marginal improvements to various internal conversion and correction factors, fundamental flaws inherent in the modeling approach still remain. The major effort of this research is to develop a new heavy-duty vehicle load-based modal emission rate model that overcomes some of the limitations of existing models and emission rates prediction methods. This model is part of the proposed Heavy-Duty Diesel Vehicle Modal Emission Modeling (HDDV-MEM) which was developed by Georgia Institute of Technology. HDDV-MEM first predicts second-by-second engine power demand as a function of vehicle operating conditions and then applies brake-specific emission rates to these activity predictions. To provide better estimates of microscopic level, this modeling approach is designed to predict second-by-second emissions from onroad vehicle operations. This research statistically analyzes the database provided by EPA and yields a model for prediction emissions at microscopic level based on engine power demand and driving mode. Research results will enhance the explaining ability of engine power demand on emissions and the importance of simulating engine power in real world applications. The modeling approach provides a significant improvement in HDDV emissions modeling compared to the current average speed cycle-based emissions models.